decay and half life

Is radioactive decay 'random' ?

• yes

• no

• sometimes

Is radioactive decay 'spontaneous' ?

• yes

• no

• sometimes

Which best describes what happens during radioactive decay?

• the emission of radioactivity

• the build up of radioactivity

• the splitting of radioactivity

• the expansion of radioactivity

What is Half-life?

• The amount of time it takes for some of the nuclei in a sample of the isotope to decay
• The amount of time it takes for half the electrons in a sample of the isotope to decay
• The amount of time it takes for half the nuclei in a sample of the isotope to decay
• the amount of time it takes to double the nuclei in a sample of the isotope to decay

Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?

• 0.25g
• 2.5g
• 25g
• 80g

What percent of carbon-14 would be left after 5730 years?

• 100%
• 75%
• 50%
• 25%

During radioactive decay ....?

• another element might be made

• another element is always made

• another element is never made

Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?

• 0.25g
• 2.5g
• 25g
• 80g

What percent of carbon-14 would be left after 5730 years?

• 100%
• 75%
• 50%
• 25%

What is the half-life of iodine-131?

• 32 days
• 8 days
• 16 days
• 24 days